Process for the solvent-free production of solid plastic moldings sealing compounds and insulations using a polyisocyanate mixture containing 2,4'-diisocyanatodiphenylmethane

Abstract

The instant invention is directed to a process for the solvent-free production of solid polyurethane moldings wherein the polyisocyanate used is a polyisocyanate mixture containing from 10 to 80% by weight of 2,4'-diisocyanatodiphenylmethane.

What is claimed is: 
     
       1. In a process for the solvent-free production of solid plastic moldings, sealing compounds and insulations based on polyurethane by reacting a reaction mixture of polyisocyanates and polyhydroxyl compounds, optionally in the presence of auxiliary agents and additives used in polyurethane chemistry, the improvement wherein the polyisocyanate used is a polyisocyanate mixture containing from 10 to 80% by weight of 2,4'-diisocyanatodiphenylmethane. 
     
     
       2. The process of claim 2, wherein said polyisocyanate mixture consists of (A) from 10 to 80% by weight of 2,4'-diisocyanatodiphenylmethane,   (B) from 20 to 70% by weight of 4,4'-diisocyanatodiphenylmethane,   (C) from 0 to 20% by weight of 2,2'-diisocyanatodiphenylmethane.   
     
     
       3. The process of claim 1, wherein said polyisocyanate mixture consists of (A) from 10 to 80% by weight of 2,4'-diisocyanatodiphenylmethane;   (B) from 20 to 70% by weight of 4,4'-diisocyanatodiphenylmethane;   (C) from 0 to 20% by weight of 2,2'-diisocyanatodiphenylmethane; and   (D) from 0 to 60% by weight of higher nuclear polyphenyl polymethylene polyisocyanate.